Exhaust Gas RECIRCULATION: Description

The exhaust gas recirculation (EGR) system is used to reduce the formation of NOx emissions. This is accomplished by recycling metered amounts of exhaust gas back into the intake system. This reduces combustion temperature and results in fewer NOx emissions.

Each system has a vacuum operated EGR valve and a vacuum modulator. Vacuum control valves (VCV), vacuum switching valves (VSV), bimetal vacuum switching valves (BVSV), vacuum transmitting valves (VTV) and thermostatic vacuum switching valves (TVSV) are used on some models to control EGR operation.